Cats with this condition lick or suck on plastic, including shower curtains or shoe laces. It’s often linked to pica, “the indiscriminate eating of inedible objects,” says Dodman, author of Pets on the Couch.

Watch: Skiing With Adorable Adventure Cat JesperpusWATCH: An energetic cat named Jesperpus hits the trails with his two-legged friend Aina Stormo in Norway.

Plastic bags is a "texture-specific eating disorder,” meaning the cats just like that texture, he adds. It’s not dangerous—unless the cat is ingesting the plastic, which can lead to intestinal blockages. (See National Geographic readers' pictures of cats.)

Cat Mats

Laura’s orange tabby grows a two-inch long winter coat, but doesn’t shed. Instead, the feline tends to pull his fur out with his teeth in spring, sometimes leaving bare patches. The fur then grows back short and smooth, getting longer in winter.

"I've mentioned this to other people, and most say this is very unusual. What do you say!?"

Some cats do engage in stress-induced hair-pulling, but the seasonal nature of this cat's behavior suggests an allergy, Dodman says. The best course of action is to take the animal to the vet to get checked out, he suggests. (Related: "What Do Cats Think About Us? You May Be Surprised.")

Long-haired cats often get mats from their winter coats, which can get itchy some spring, adds John Bradshaw of the U.K.'s University of Bristol and author of The Trainable Cat.

The pets sometimes “will try to shift the [mats] with their teeth,” which can leave bald patches.

The Young and the Restless

Katelynn Davis’ foundling cat, rescued from behind a restaurant, used to sleep on her shoulder. Now, at two years old, he has what's sometimes called the “zoomies,” randomly darting around the house and meowing constantly, often while sitting by the door.

"It's frustrating, I love him and I want what is best for him, but I'm not sure what to do anymore," Davis tells us.

The zoomies are also a sign that cat isn’t getting enough aerobic exercise, Dodman explains. The natural pattern of cats, big and small, is to “sleep or nap and then have sudden bursts of activity. That’s how they hunt,” he says.

Those bursts come randomly if they don’t get enough physical activity.

Getting the cat to play with store-bought or DIY toys, with you or on his own, will help. Zoomies you control will minimize the zoomies you don’t.

Nod tiredly if you’ve ever had a cat jump on you at 4 a.m. and run across you like a bridge.